In recent years, a technique for displaying stereoscopic images by an image display device has been employed. At the time of viewing such a stereoscopic image displayed by the image display device, focal distance differs even if the real world and the angle of convergence are the same, which becomes a factor for causing visual fatigue. In particular, a case where change in disparity is great, such as a case where a certain portion within a screen protrudes extremely, or a case where an object improperly protrudes during display of a moving image, or the like, becomes a burden on a viewer.
Therefore, conventionally, in order to perform natural stereoscopic display, a technique has been proposed wherein the degree of protrusion, and depth feel are adjusted by setting an offset for shifting the right image to the right side or left side as to the left image (e.g., see PTL 1).